1 | /* Copyright (c) 2006-2010 by OpenLayers Contributors (see authors.txt for |
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2 | * full list of contributors). Published under the Clear BSD license. |
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3 | * See http://svn.openlayers.org/trunk/openlayers/license.txt for the |
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4 | * full text of the license. */ |
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5 | |
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6 | |
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7 | /** |
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8 | * @requires OpenLayers/Util.js |
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9 | * @requires OpenLayers/Style.js |
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10 | * @requires OpenLayers/Symbolizer/Point.js |
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11 | * @requires OpenLayers/Symbolizer/Line.js |
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12 | * @requires OpenLayers/Symbolizer/Polygon.js |
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13 | * @requires OpenLayers/Symbolizer/Text.js |
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14 | * @requires OpenLayers/Symbolizer/Raster.js |
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15 | */ |
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16 | |
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17 | /** |
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18 | * Class: OpenLayers.Rule |
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19 | * This class represents an SLD Rule, as being used for rule-based SLD styling. |
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20 | */ |
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21 | OpenLayers.Rule = OpenLayers.Class({ |
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22 | |
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23 | /** |
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24 | * Property: id |
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25 | * {String} A unique id for this session. |
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26 | */ |
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27 | id: null, |
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28 | |
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29 | /** |
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30 | * APIProperty: name |
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31 | * {String} name of this rule |
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32 | */ |
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33 | name: null, |
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34 | |
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35 | /** |
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36 | * Property: title |
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37 | * {String} Title of this rule (set if included in SLD) |
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38 | */ |
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39 | title: null, |
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40 | |
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41 | /** |
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42 | * Property: description |
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43 | * {String} Description of this rule (set if abstract is included in SLD) |
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44 | */ |
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45 | description: null, |
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46 | |
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47 | /** |
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48 | * Property: context |
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49 | * {Object} An optional object with properties that the rule should be |
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50 | * evaluated against. If no context is specified, feature.attributes will |
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51 | * be used. |
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52 | */ |
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53 | context: null, |
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54 | |
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55 | /** |
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56 | * Property: filter |
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57 | * {<OpenLayers.Filter>} Optional filter for the rule. |
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58 | */ |
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59 | filter: null, |
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60 | |
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61 | /** |
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62 | * Property: elseFilter |
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63 | * {Boolean} Determines whether this rule is only to be applied only if |
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64 | * no other rules match (ElseFilter according to the SLD specification). |
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65 | * Default is false. For instances of OpenLayers.Rule, if elseFilter is |
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66 | * false, the rule will always apply. For subclasses, the else property is |
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67 | * ignored. |
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68 | */ |
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69 | elseFilter: false, |
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70 | |
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71 | /** |
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72 | * Property: symbolizer |
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73 | * {Object} Symbolizer or hash of symbolizers for this rule. If hash of |
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74 | * symbolizers, keys are one or more of ["Point", "Line", "Polygon"]. The |
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75 | * latter if useful if it is required to style e.g. vertices of a line |
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76 | * with a point symbolizer. Note, however, that this is not implemented |
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77 | * yet in OpenLayers, but it is the way how symbolizers are defined in |
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78 | * SLD. |
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79 | */ |
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80 | symbolizer: null, |
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81 | |
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82 | /** |
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83 | * Property: symbolizers |
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84 | * {Array} Collection of symbolizers associated with this rule. If |
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85 | * provided at construction, the symbolizers array has precedence |
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86 | * over the deprecated symbolizer property. Note that multiple |
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87 | * symbolizers are not currently supported by the vector renderers. |
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88 | * Rules with multiple symbolizers are currently only useful for |
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89 | * maintaining elements in an SLD document. |
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90 | */ |
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91 | symbolizers: null, |
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92 | |
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93 | /** |
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94 | * APIProperty: minScaleDenominator |
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95 | * {Number} or {String} minimum scale at which to draw the feature. |
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96 | * In the case of a String, this can be a combination of text and |
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97 | * propertyNames in the form "literal ${propertyName}" |
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98 | */ |
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99 | minScaleDenominator: null, |
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100 | |
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101 | /** |
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102 | * APIProperty: maxScaleDenominator |
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103 | * {Number} or {String} maximum scale at which to draw the feature. |
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104 | * In the case of a String, this can be a combination of text and |
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105 | * propertyNames in the form "literal ${propertyName}" |
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106 | */ |
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107 | maxScaleDenominator: null, |
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108 | |
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109 | /** |
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110 | * Constructor: OpenLayers.Rule |
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111 | * Creates a Rule. |
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112 | * |
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113 | * Parameters: |
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114 | * options - {Object} An optional object with properties to set on the |
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115 | * rule |
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116 | * |
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117 | * Returns: |
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118 | * {<OpenLayers.Rule>} |
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119 | */ |
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120 | initialize: function(options) { |
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121 | this.symbolizer = {}; |
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122 | OpenLayers.Util.extend(this, options); |
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123 | if (this.symbolizers) { |
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124 | delete this.symbolizer; |
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125 | } |
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126 | this.id = OpenLayers.Util.createUniqueID(this.CLASS_NAME + "_"); |
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127 | }, |
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128 | |
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129 | /** |
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130 | * APIMethod: destroy |
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131 | * nullify references to prevent circular references and memory leaks |
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132 | */ |
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133 | destroy: function() { |
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134 | for (var i in this.symbolizer) { |
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135 | this.symbolizer[i] = null; |
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136 | } |
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137 | this.symbolizer = null; |
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138 | delete this.symbolizers; |
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139 | }, |
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140 | |
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141 | /** |
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142 | * APIMethod: evaluate |
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143 | * evaluates this rule for a specific feature |
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144 | * |
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145 | * Parameters: |
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146 | * feature - {<OpenLayers.Feature>} feature to apply the rule to. |
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147 | * |
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148 | * Returns: |
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149 | * {Boolean} true if the rule applies, false if it does not. |
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150 | * This rule is the default rule and always returns true. |
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151 | */ |
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152 | evaluate: function(feature) { |
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153 | var context = this.getContext(feature); |
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154 | var applies = true; |
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155 | |
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156 | if (this.minScaleDenominator || this.maxScaleDenominator) { |
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157 | var scale = feature.layer.map.getScale(); |
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158 | } |
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159 | |
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160 | // check if within minScale/maxScale bounds |
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161 | if (this.minScaleDenominator) { |
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162 | applies = scale >= OpenLayers.Style.createLiteral( |
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163 | this.minScaleDenominator, context); |
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164 | } |
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165 | if (applies && this.maxScaleDenominator) { |
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166 | applies = scale < OpenLayers.Style.createLiteral( |
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167 | this.maxScaleDenominator, context); |
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168 | } |
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169 | |
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170 | // check if optional filter applies |
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171 | if(applies && this.filter) { |
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172 | // feature id filters get the feature, others get the context |
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173 | if(this.filter.CLASS_NAME == "OpenLayers.Filter.FeatureId") { |
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174 | applies = this.filter.evaluate(feature); |
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175 | } else { |
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176 | applies = this.filter.evaluate(context); |
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177 | } |
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178 | } |
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179 | |
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180 | return applies; |
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181 | }, |
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182 | |
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183 | /** |
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184 | * Method: getContext |
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185 | * Gets the context for evaluating this rule |
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186 | * |
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187 | * Paramters: |
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188 | * feature - {<OpenLayers.Feature>} feature to take the context from if |
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189 | * none is specified. |
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190 | */ |
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191 | getContext: function(feature) { |
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192 | var context = this.context; |
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193 | if (!context) { |
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194 | context = feature.attributes || feature.data; |
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195 | } |
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196 | if (typeof this.context == "function") { |
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197 | context = this.context(feature); |
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198 | } |
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199 | return context; |
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200 | }, |
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201 | |
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202 | /** |
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203 | * APIMethod: clone |
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204 | * Clones this rule. |
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205 | * |
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206 | * Returns: |
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207 | * {<OpenLayers.Rule>} Clone of this rule. |
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208 | */ |
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209 | clone: function() { |
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210 | var options = OpenLayers.Util.extend({}, this); |
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211 | if (this.symbolizers) { |
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212 | // clone symbolizers |
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213 | var len = this.symbolizers.length; |
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214 | options.symbolizers = new Array(len); |
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215 | for (var i=0; i<len; ++i) { |
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216 | options.symbolizers[i] = this.symbolizers[i].clone(); |
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217 | } |
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218 | } else { |
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219 | // clone symbolizer |
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220 | options.symbolizer = {}; |
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221 | var value, type; |
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222 | for(var key in this.symbolizer) { |
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223 | value = this.symbolizer[key]; |
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224 | type = typeof value; |
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225 | if(type === "object") { |
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226 | options.symbolizer[key] = OpenLayers.Util.extend({}, value); |
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227 | } else if(type === "string") { |
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228 | options.symbolizer[key] = value; |
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229 | } |
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230 | } |
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231 | } |
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232 | // clone filter |
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233 | options.filter = this.filter && this.filter.clone(); |
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234 | // clone context |
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235 | options.context = this.context && OpenLayers.Util.extend({}, this.context); |
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236 | return new OpenLayers.Rule(options); |
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237 | }, |
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238 | |
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239 | CLASS_NAME: "OpenLayers.Rule" |
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240 | }); |
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